Controls on fracture openness and reactivation in Forsmark, Sweden

Autor: Doolaeghe, Diane, Darcel, Caroline, Selroos, Jan-Olof, Ivars, Diego Mas, Davy, Philippe
Přispěvatelé: Itasca Consultants, Royal Institute of Technology [Stockholm] (KTH ), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2023
Předmět:
Zdroj: Scientific Reports
Scientific Reports, 2023, 13 (1), pp.6686. ⟨10.1038/s41598-023-33619-9⟩
ISSN: 2045-2322
DOI: 10.1038/s41598-023-33619-9
Popis: In crystalline bedrock, the open fraction of the fracture network constitutes the main pathways for fluids. Many observations point out that the state of stress influences the open fraction, likely indicating recent reactivation. But how this occurs is still unresolved. We analyse the conditions for fracture reactivation from fracture data collected in the uppermost 1 km of bedrock in Forsmark, Sweden. The open fraction is mainly correlated to the stress acting normally on the fracture but even away from critical failure, leading us to analyse the potential fluid pressure required for reactivation, $${P}_{c}$$ P c . We observe that 100% of the fractures are open when $${P}_{c}$$ P c is hydrostatic, and the ratio decreases exponentially to a plateau of ~ 17% when $${P}_{c}$$ P c is lithostatic and above. Exceptions are the oldest fractures, having a low open fraction independent of $${P}_{c}$$ P c . We suggest that these results reflect past pressure build-ups, potentially related to recent glaciations, and developing only if the preexisting open fraction is large enough.
Databáze: OpenAIRE
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